Sums of variables at the onset of chaos

We explain how specific dynamical properties give rise to the limit distribution of sums of deterministic variables at the transition to chaos via the period-doubling route. We study the sums of successive positions generated by an ensemble of initial conditions uniformly distributed in the entire phase space of a unimodal map as represented by the logistic map. We find that these sums acquire their salient, multiscale, features from the repellor preimage structure that dominates the dynamics toward the attractors along the period-doubling cascade. And we explain how these properties transmit from the sums to their distribution. Specifically, we show how the stationary distribution of sums of positions at the Feigebaum point is built up from those associated with the supercycle attractors forming a hierarchical structure with multifractal and discrete scale invariance properties.Comment: arXiv admin note: text overlap with arXiv:1312.071

Scaling of distributions of sums of positions for chaotic dynamics at band-splitting points

The stationary distributions of sums of positions of trajectories generated by the logistic map have been found to follow a basic renormalization group (RG) structure: a nontrivial fixed-point multi-scale distribution at the period-doubling onset of chaos and a Gaussian trivial fixed-point distribution for all chaotic attractors. Here we describe in detail the crossover distributions that can be generated at chaotic band-splitting points that mediate between the aforementioned fixed-point distributions. Self affinity in the chaotic region imprints scaling features to the crossover distributions along the sequence of band splitting points. The trajectories that give rise to these distributions are governed first by the sequential formation of phase-space gaps when, initially uniformly-distributed, sets of trajectories evolve towards the chaotic band attractors. Subsequently, the summation of positions of trajectories already within the chaotic bands closes those gaps. The possible shapes of the resultant distributions depend crucially on the disposal of sets of early positions in the sums and the stoppage of the number of terms retained in them

The underlying social dynamics of paradigm shifts

We develop here a multi-agent model of the creation of knowledge (scientific progress or technological evolution) within a community of researchers devoted to such endeavors. In the proposed model, agents learn in a physical-technological landscape, and weight is attached to both individual search and social influence. We find that the combination of these two forces together with random experimentation can account for both i) marginal change, that is, periods of normal science or refinements on the performance of a given technology (and in which the community stays in the neighborhood of the current paradigm); and ii) radical change, which takes the form of scientific paradigm shifts (or discontinuities in the structure of performance of a technology) that is observed as a swift migration of the knowledge community towards the new and superior paradigm. The efficiency of the search process is heavily dependent on the weight that agents posit on social influence. The occurrence of a paradigm shift becomes more likely when each member of the community attaches a small but positive weight to the experience of his/her peers. For this parameter region, nevertheless, a conservative force is exerted by the representatives of the current paradigm. However, social influence is not strong enough to seriously hamper individual discovery, and can act so as to empower successful individual pioneers who have conquered the new and superior paradigm.Fil: Rodriguez Sickert, Carlos. Universidad del Desarrollo; ChileFil: Cosmelli, Diego. Pontificia Universidad Católica de Chile; ChileFil: Claro, Francisco. Pontificia Universidad Católica de Chile; ChileFil: Fuentes, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad San Sebastián; Chil

First passage time on pattern formation in a non-local Fisher population dynamics

We use stochastic dynamics to develop the patterned attractor of a non?local extended system. This is done analytically using the stochastic path perturbation approach scheme, where a theory of perturbation in the small noise parameter is introduced to analyze the random escape of the stochastic field from the unstable state. Emphasis is placed on the specific mode selection that these types of systems exhibit. Concerning the stochastic propagation of the front we have carried out Monte Carlo simulations which coincide with our theoretical predictions.Fil: Fuentes, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Desarrollo. Facultad de Gobierno. Centro de Investigación en Complejidad Social; Chile. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); ArgentinaFil: Caceres Garcia Faure, Manuel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentin

El modelo de gestión en la educación especial. La calidad de atención de las necesidades educativas especiales

Una investigación de tipo cualitativo abordó, desde la etnografía y mediante un estudio de caso, el ámbito de la educación especial y de los que trabajan en ella, como docentes de apoyo de las Unidades de Servicio y Apoyo a la Escuela Regular (usaer), quienes intervienen en dos planteles escolares de Educación Básica para atender a los alumnos que presentan necesidades educativas especiales (nee). En particular, se estudió el impacto del modelo de gestión en la calidad educativa. En un contexto mundial donde prevalecen sistemas económicos, sociales y educativos en crisis, con una fuerte influencia de diversas agencias internacionales que definen las políticas públicas y educativas en México, los resultados indican que la racionalidad técnico instrumental y de la administración clásica escolar que dirigen el modelo de gestión, se traducen en poca calidad en la atención de las nee. No obstante, en la práctica docente emerge un modelo de gestión alterno, sociohistórico, próximo a paradigmas de la complejidad que responden más a la subjetividad y a la diversidad educativa de las organizaciones escolares

Stochastic Path Perturbation Approach Applied to Non-Local Non-Linear Equations in Population Dynamics

We described the first passage time distribution associated to the stochastic evolution from an unstable uniform state to a patterned one (attractor of the system), when the time evolution is given by an integro-differential equation describing a population model. In order to obtain analytical results we used the Stochastic Path Perturbation Approach introducing a minimum coupling approximation into the nonlinear dynamics, and a stochastic multiscale perturbation expansion. We show that the stochastic multiscale perturbation is a necessary tool to handle other problems like: nonlinear instabilities and multiplicative stochastic partial differential equations. A small noise parameter was introduced to define the random escape of the stochastic field. We carried out Monte Carlo simulations in a non-local Fisher like equation, to show the agreement with our theoretical predictions.Fil: Fuentes, Miguel Angel. Santa Fe Institute; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Filosóficas. - Sociedad Argentina de Análisis Filosófico. Instituto de Investigaciones Filosóficas; Argentina. Universidad San Sebastian.; ChileFil: Caceres Garcia Faure, Manuel Osvaldo. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Nonequilibrium evolution of volatility in origination and extinction explains fat-tailed fluctuations in Phanerozoic biodiversity

Fluctuations in biodiversity, large and small, pervade the fossil record, yet we do not understand the processes generating them. Here, we extend theory from nonequilibrium statistical physics to describe the fat-tailed form of fluctuations in Phanerozoic marine invertebrate richness. Using this theory, known as superstatistics, we show that heterogeneous rates of origination and extinction between clades and conserved rates within clades account for this fat-tailed form. We identify orders and families as the taxonomic levels at which clades experience interclade heterogeneity and within-clade homogeneity of rates, indicating that families are subsystems in local statistical equilibrium, while the entire system is not. The separation of timescales between within-clade background rates and the origin of major innovations producing new orders and families allows within-clade dynamics to reach equilibrium, while between-clade dynamics do not. The distribution of different dynamics across clades is consistent with niche conservatism and pulsed exploration of adaptive landscapes.Fil: Rominger, Andrew J.. No especifíca;Fil: Fuentes, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Filosóficas. - Sociedad Argentina de Análisis Filosófico. Instituto de Investigaciones Filosóficas; Argentina. Universidad San Sebastián; ChileFil: Marquet, Pablo A.. Pontificia Universidad Católica de Chile; Chile. Instituto de Ecología y Biodiversidad; Chile. Universidad Nacional Autónoma de México; Méxic

Microhardness of different resin cement shades inside the root canal

Objectives: To compare microhardness along the root canal post space of two resin cements in different shades and a dual-cure resin core material. Study D esign: Root canals of 21 bovine incisors were prepared for post space. Translucent posts (X?Post, Dentsply DeTrey) were luted using one the following resin luting agent: Calibra (Dentsply DeTrey) in Translucent, Medium and Opaque shades, RelyX Unicem (3M ESPE) in Translucent, A2 and A3 shades and the dual-cure resin core material Core?X flow. All materials were applied according to manufacturers? instructions and were all photopolymerized (Bluephase LED unit, Ivoclar Vivadent, 40s). After 24 hours, roots were transversally cut into 9 slices 1 mm thick from the coronal to apical extremes, three corresponding to each root third. Then, VHNs were recorded (100gf, 30 s) on the resin luting materials along the adhesive interface in all sections. Data were analyzed by two- way ANOVA and SNK tests (?=0.05). Results: A significant influence on microhardness of resin luting material in their respective shades (p<0.001), root third (p<0.001) and interactions between them was detected (p<0.001). RelyX Unicem cement showed the highest microhardness values and Calibra the lowest, regardless of the shade selected. All resin luting materials tested exhibited a significantly higher microhardness in the cervical third. Conclusions: Microhardness of resin luting agents tested inside the canal is dependent on material brand and resin cement shade seems to be a less relevant factor. Microhardness decreased along the root canal, regardless of the shade selecte

Hydrophilicity of Mordenites with Different SiO[2]/Al[2]O[3] Molar Ratio

Hydrophicility of H-mordenites with SiO[2]/Al[2]O[3] molar ratio (MR) varying in the range from 10 up to 206 was investigated by IR spectroscopy, TPD of ammonia and thermogravimetry methods. It was found that dealuminated mordenite retains affinity for water in the entire MR range, in contrast to published results for synthetic pentasil zeolites. In H-mordenites extra-framework aluminum exists in the form of dimers of aluminum hydroxide, those presumably are stabilized in the channels of mordenite. An inversely proportional correlation between the water content in pores and the concentration of channel Lewis sites was observed

Digital Outburst: The Expression of a Social Crisis through Online Social Networks

There is a growing concern about the effects that the relationship between the activity of society in the physical world and in the digital world could have. In this study, we address this question in a context of social crisis. Our quantitative and qualitative analysis of the data associated with the critical process suggests a deep and nontrivial relationship between both worlds. Perhaps the most important result refers to the leading role of language, its meaning, and symbolism in the development of social transformation processes linked to the complexity of the social system and its adaptive nature.Fil: Cárdenas, Juan Pablo. No especifíca;Fil: Urbina, Carolina. Pontificia Universidad Católica de Valparaíso; ChileFil: Vidal, Gerardo. Pontificia Universidad Católica de Valparaíso; ChileFil: Olivares, Gastón. No especifíca;Fil: Fuentes, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Filosóficas. - Sociedad Argentina de Análisis Filosófico. Instituto de Investigaciones Filosóficas; Argentin